Autofocus apparatus

摘要

An autofocus apparatus includes a target position calculator for calculating a focus lens target position based on a defocus amount obtained based on the signal of focus detector of a phase difference detecting type and a focus lens position, a target position memory for storing the target position, a speed calculator for calculating an object speed in an optical axis direction based on a present target position, the previous target position, and time period between calculations of present target position and prior target position, and a lens controller for setting, when the object speed changes, a focus lens drive speed based on the present target position, the focus lens position and the object speed and setting, when the object speed does not change, the focus lens drive speed based on a present drive speed, a present defocus amount, and a previous defocus amount.

主权项

1. An autofocus apparatus comprising:
a memory; and a lens controller, which includes a processor, configured to execute: a target position calculating task that calculates a target position of a focus lens based on a defocus amount obtained based on a signal from a focus detector of a phase difference detecting type and a position of the focus lens obtained by a position detector; a target position storing task that stores in the memory the calculated target position; an object speed calculating task that calculates an object speed in an optical axis direction based on a present target position, a target position calculated prior to calculating of the present target position, and one of a target position calculation time consumed from a time at which the target position calculating task calculates the target position calculated prior to calculating of the present target position to a time at which the target position calculating task calculates the present target position or a time regarded as equivalent to the target position calculation time; a first drive speed setting task that sets a drive speed of the focus lens based on the present target position, the position of the focus lens, and the object speed; a second drive speed setting task that sets the drive speed of the focus lens based on a present drive speed of the focus lens, a present defocus amount, and the defocus amount obtained prior to obtaining of the present defocus amount; an object speed change determining task that determines whether or not the object speed changes; a first driving task that drives the focus lens based on the drive speed set by the first drive speed setting task in a case where the object speed has been determined to change; and
a second driving task that drives the focus lens based on the drive speed set by the second drive speed setting task in a case where the object speed has been determined to not change.